A. Field of the Invention
The field of the present invention relates generally to continuous belt systems configured for carrying bulk materials thereon. More particularly, the present invention relates to such continuous belt systems having a plurality of trough roller assemblies supporting the conveyor belt in a generally trough-like configuration. Even more particularly the present invention relates to a trough roller assembly having a pair of shafts defining the trough configuration.
B. Background
Continuous belt conveyor systems are commonly utilized to carry bulk materials, including trash, recyclables, gravel, coal, aggregate and many other types of materials, from one location to another, sometimes over long distances. One well known configuration for such conveyor systems has a continuous belt that comprises an upper flight section which carries the bulk materials to a location where it is dumped off the end of the conveyor belt for disposal or further processing and a lower flight section that returns the belt to a position where it can receive more bulk materials. A supporting framework supports roller assemblies, placed at appropriate intervals, over which the generally flexible belt travels in the upper and lower flight sections. To better maintain the bulk materials on the belt when traveling through the upper flight section, it is common to arrange the roller assemblies in the upper flight section in a generally trough or trough-like cross section that defines the belt in a corresponding configuration. These roller assemblies are commonly referred to as trough roller assemblies. The lower flight section is typically supported by roller assemblies comprising a single roller that supports the flexible belt in a generally flat or horizontal configuration. These roller assemblies are commonly referred to as return roller assemblies.
The present invention is directed to an improved trough roller assembly for carrying bulk materials. The prior art trough roller assemblies comprise a plurality of separate rollers that are cooperatively configured in the trough-like configuration. In a typical configuration, three rollers are utilized, one in the center that is positioned generally horizontal to define the bottom of the trough and one at each end or wing of the center roller that are angled in a generally upward direction to define the sides of the trough. Brackets mounted onto the framework separate the rollers and provide the desired trough-shaping angle for each roller. The rollers, commonly referenced as idler rollers, are rotatably attached to the brackets. In one common configuration, brackets support both ends of the idler rollers. Examples of this configuration are shown in U.S. Pat. No. 6,550,606 to Tapp, U.S. Pat. No. 6,349,819 to Nohl, U.S. Pat. No. 5,373,935 to Anderson, U.S. Pat. No. 4,029,200 to Dillon and U.S. Pat. No. 3,545,602 to McCullagh. These patents show the use of a pair of center brackets configured to rotatably support the center roller in a generally horizontal position and two pairs of side brackets that rotatably support the side or wing rollers in the angled position. In another configuration of three-roller trough roller assemblies, a single pair of support brackets rotatably support the center roller in a generally horizontal position and rotatably support, in a cantilever fashion, the side or wing rollers to define the trough. An example of this type of trough roller assembly is shown in U.S. Pat. No. 4,266,662 to Reid. In a two-roller configuration, a single bracket rotatably supports two rollers, both in an angled and cantilever fashion, to define a generally v-shaped trough. Examples of this type of trough roller assembly are shown in U.S. Pat. No. 4,903,820 to Fyfe, U.S. Pat. No. 4,830,179 to Fyfe and U.S. Pat. No. 4,032,002 to Jackson. In each of the above configurations, the flexible belt is configured to correspond to the trough cross-section defined by the rollers and slide over the rollers as it carries the bulk materials.
The presently available trough roller assemblies have some well known problems that the present invention overcomes. The primary problem, results from the fact that the existing roller assemblies utilize bearings that cannot be greased. Because the rotating ends of the rollers are exposed where they connect to the bearings and brackets, they are known to become clogged with debris, typically from the bulk materials being transferred over the upper flight section. As an example, in recycling operations where the conveying system is utilized to convey waste materials for further processing, it is well known that waste particles can clog the bearings. Problems with other materials are also well known. When the bearings become clogged, they freeze-up and stop rotating. When this happens the belt is then sliding over a stationary roller, which has a relatively thin metal shell that, over time, is gradually ablated away. If not fixed, the roller will form jagged edges that will cut into the conveyor belt. Avoiding clogging of the ends of the rollers require frequent maintenance in order to prevent damage to the rollers, belt and the belt system itself. Even with frequent maintenance these rollers typically require frequent replacement. In addition to the direct cost of purchasing new rollers and having personnel install the rollers, clogging of the rollers in the trough roller assembly can significantly impact the efficient operation of the belt system and, therefore, the use or processing of the materials carried in the upper flight section.
What is needed, therefore, is an improved configuration for a trough roller assembly that substantially reduces or eliminates debris clogging the rotating mechanism, a problem which is prevalent among presently available trough roller assemblies. The preferred trough roller assembly should substantially shield the rotating connections from being clogged with debris or other material so as to reduce the need for maintenance and/or replacement. The preferred trough roller assembly should comprise a minimum number of moving parts and be adaptable for a variety of different trough roller shapes and bulk materials. Preferably, the improved trough roller assembly will be adaptable to being manufactured out of materials and components that provide a lower cost trough roller assembly for use in various industrial and commercial enterprises.